Rolling-based manipulation for multiple objects

This paper discusses the manipulation of multiple objects under rolling contacts. For manipulating multiple objects, the following two key issues do not arise in the manipulation of a single object: 1) each object's motion is restricted by the other objects; and 2) the contact force among objects is not controlled directly. As for (1), we first formulate the motion constraint for the whole grasp system, and then provide a necessary condition for manipulating multiple objects uniquely. As for (2), we provide a condition for determining the contact forces among objects uniquely. We further show a sufficient condition for manipulating multiple objects within the object motion constraint. Under this sufficient condition, we propose a control scheme for object motion by taking the motion constraint into account. Simulation and experimental results are provided to confirm our idea.